1. Field of the Invention
The invention relates generally to speaker enclosure devices, and relates specifically to an apparatus for re-radiating the sound emanating from a speaker enclosed and supported therein.
2. Description of the Prior Art
Presently known speaker enclosures include rigid walls, which absorb the sound radiating from the back of the speaker. Back of speaker sound is out of phase with respect to the sound radiating from the front of the speaker, and would, if not absorbed or modified, cancel at low frequencies, and interfere at high frequencies, with the sound radiating from the front of the speaker. Such presently known speaker enclosures can waste half of the sound being produced by the speaker, specifically the sound radiating from the back of the speaker.
Further, other presently known speaker enclosures, such as bass reflex systems, isolate the back of speaker sound wave, in low frequencies, by tuning the enclosed volume of air through a reflex opening to a resonant frequency. The indirect pressure emitted from the reflex opening undergoes a phase displacement such that it intensifies the front wave. Such enclosures are effective over less than half an octave around the resonant frequency, and provides little additional sound radiation beyond that provided by the enclosure without the reflex opening at other frequencies.
Sound, as recorded, includes two components, the "direct" sound, which reaches the microphones directly from the primary sound source, and "apparent" sound, which reaches the microphones from all other locations. The sound which is reproduced then includes such two components of the sound field, the direct and apparent sound, which originated from locations that are different from each other.
The apparent sound includes reverberant sound from the environment boundaries, and ambient sounds. The listener listens for reverberant and ambient sounds which occur at certain expected points in time, and excludes those which occur later or sooner. Apparent sound, by virtue of such difference in location with respect to direct sound, is not effectively reproduced by stereo speakers.
In professional sound environments, as a professional studio, the room is generally small. Rooms of small size have generally poor acoustic properties, as they do not provide sufficient reverberation time for the reverberant portion of the sound. To get longer reverberations time, a larger room is required, but large rooms are not convenient for operational reasons.
In home sound environments, a listening room is not designed with acoustics in mind, and such rooms also have generally poor acoustic properties.
Presently known speaker enclosures do not affect the boundaries of the sound listening environment and do not accurately reproduce and radiate apparent sound. Further, such enclosures "waste" the apparent sound that is available in the stereo program material.